March 2014 

NASA/CR–2014-218184

Frequency of Specific Categories of Aviation 

Accidents and Incidents During 2001-2010 

 Joni K. Evans 

 Analytical Mechanics Associates, Inc., Hampton, Virginia 
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March 2014 

NASA/CR–2014-218184

Frequency of Specific Categories of Aviation 

Accidents and Incidents During 2001-2010 

Joni K. Evans 

Analytical Mechanics Associates, Inc., Hampton, Virginia 
Available from: 

NASA Center for AeroSpace Information 

7115 Standard Drive 

Hanover, MD 21076-1320 

443-757-5802 

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National Aeronautics and Space Administration. 
Introduction

The primary purpose of the analysis reported here is to identify the types of accidents and 

incidents with the greatest impact on the overall safety risk in U.S. civil aviation. The 

safety risk is here defined to include five elements: 

x the number of total accidents 

x the number of fatal accidents 

x the number of incidents 

x the number of total injuries 

x the number of fatal injuries 

Accident types have been shown to vary considerably among different flight operations 

(e.g., large air carriers versus general aviation). For this reason, all analyses were done 

separately for four types of flight operations (Part 121, Scheduled Part 135, NonScheduled Part 135 and Part 91). 

Nomenclature

NTSB National Transportation Safety Board 

FAA Federal Aviation Administration 

CAST Commercial Aviation Safety Team 

ICAO International Civil Aviation Organization 

CICTT CAST/ICAO Common Taxonomy Team 

ARC Abnormal Runway Contact 

AMAN Abrupt Maneuver 

ADRM Aerodrome 

ATM Air Traffic Management 

BIRD Bird Strike 

CABIN Cabin Safety Events 

CTOL Collision with Obstacle(s) during Takeoff and Landing 

CFIT Controlled Flight Into or toward Terrain 

CWO-PL Collision with Object – Precautionary Landing

CWT-PL Collision with Terrain – Precautionary Landing

EVAC Evacuation 

EWT-PL Encounter with Terrain – Precautionary Landing 

FI-NI Fire/Smoke Non-Impact 

FI-POST Fire/Smoke Post-Impact 

FUEL Fuel Related 

GCOL Ground Collision 

ICE Icing 

INCAP Pilot Incapacitation or Severe Impairment 

LOC-G Loss of Control – Ground 

LOC-I Loss of Control – In flight 

1
LALT Low Altitude Operations 

MAC Airprox/TCAS Alert/Loss of Separation/Near Mid-Air Collision/ 

 Mid-Air Collision 

PL-FUEL Loss of Engine Power – Fuel Related (same as FUEL) 

PL-OTHER Loss of Engine Power – Other Reasons 

PL-UNK Loss of Engine Power – Unknown Reasons 

RAMP Ground Handling 

RE or RUNEXC Runway Excursion 

RI-VAP Runway Incursion – Vehicle, Aircraft or Person 

SEC Security Related 

SCF-NP System/Component Failure or Malfunction – Non-powerplant 

SCF-PP System/Component Failure or Malfunction – Powerplant 

SCF-SLE System/Component Failure or Malfunction (Stress Limits Exceeded) 

TURB Turbulence Encounter 

UIMC Unintended Flight in Instrument Meteorological Conditions 

USOS Undershoot/Overshoot 

WSTRW Windshear or Thunderstorm 

Data Sources 

The National Transportation Safety Board (NTSB) is an independent federal agency that 

investigates every civil aviation accident in the United States and significant accidents in 

the other modes of transportation, conducts special investigations and safety studies, and 

issues safety recommendations to prevent future accidents. The information the NTSB 

investigators collect during their investigations of these aviation events resides in the 

NTSB Aviation Accident and Incident Data System. A copy of this database in Microsoft 

Access format was obtained from the Aviation Safety Information Analysis and Sharing 

(ASIAS) department of the Federal Aviation Administration’s Office of Aviation Safety1

in June 2012. At that point in time, the NTSB investigation was not complete for a 

substantial number of 2011 accidents, particularly those which occurred toward the end 

of the year. For this reason, all work on the database was restricted to 1987-2010, which 

was primarily an update of two years beyond the previous working version of the data. 

The update process requires several months of cross-checking various data elements and 

attempting to fill in any missing data, followed by the assignment of occurrence 

categories to each accident. 

The NTSB database includes events involving a wide variety of aircraft (airplanes, 

helicopters, hot air balloons, gliders, ultralight, etc.) with operations conducted under 

various Federal Aviation Regulations (Part 91: General Aviation, Part 121: Commercial 

Air Carriers, Part 129: Foreign Air Carriers, Part 135: Commuters and On-Demand Air 

Taxis, Part 137: Agricultural Operations, etc.). In March 1997 a change was made in the 

Federal Aviation Regulations defining the requirements for Part 121 versus Part 135 

1

 http://www.asias.faa.gov/portal/page/portal/asias_pages/asias_home/ 

2
operations. As a result, Part 121 regulations were applied to commuter operations with 10 

or more passengers2

.

The NTSB considers each event to be either an accident or an incident, under the 

following definitions:3

Accident - an occurrence associated with the operation of an aircraft, which takes 

place between the time any person boards the aircraft with the intention of 

flight and all such persons have disembarked, and in which any person 

suffers death or serious injury, or in which the aircraft receives substantial 

damage 

Incident - an occurrence other than an accident, associated with the operation of an 

aircraft, which affects or could affect the safety of operations 

Any injury or aircraft damage which occurs when there was no intent for flight (high 

speed taxi tests, movement of the aircraft around the airfield, maintenance run-ups, etc) 

is, by definition, an incident. 

The NTSB does not investigate all incidents, but incidents as well as accidents are 

reported to the Federal Aviation Administration (an agency within the Department of 

Transportation) by pilots, airport personnel and private citizens. The FAA maintains a 

database with the information that they receive in these reports and collect in their 

investigations. A copy of the FAA’s Accident/Incident Data System (AIDS) in Microsoft 

Access format was obtained from ASIAS in July of 2011, which was late enough in the 

year that nearly all incidents from 2010 had been investigated. The current working copy 

of the AIDS database includes incidents from 1985-2010. 

Among the incidents in this dataset were some mid-air collisions and ground collisions 

between multiple aircraft. The AIDS database includes a record for each aircraft 

involved, unless the aircraft was parked and unoccupied. In order to reduce the analysis 

data set to one record for each incident, each of the incidents involving multiple aircraft 

was reviewed, and the report for the passive aircraft (i.e., the aircraft that was hit during 

the collision) was eliminated. This procedure was not followed for the accident data for 

two reasons. First, in an accident the level of aircraft damage and injury can vary 

substantially between the two aircraft involved. Secondly, in an incident, the blame most 

often lies with the moving aircraft, whereas in an accident more parties may be at fault. 

All recorded accidents and incidents involving commercially built fixed-wing airplanes 

operating under FAR Part 121, Part 135 or Part 91 were included in these working 

datasets, regardless of whether the investigation is in a preliminary stage or finalized, and 

whether or not the event occurred within the United States. Amateur built or experimental 

aircraft were excluded, as were helicopters, ultra light aircraft, gliders and balloons. Also 

2 National Transportation Safety Board. Annual Review of Aircraft Accident Data US Air Carrier 

Operations, Calendar Year 1999, NTSB/ARC-02/03, PB2002-109241, November 13, 2002, page 1.

3

 National Transportation Safety Board, “Government Information Locator Service (GILS): Aviation 

Accident Synopses”’ http://ntsb.gov/Info/gils/gilssyn.htm

3
excluded were sky diving incidents in which the main issue involved the parachute or the 

parachutist, rather than the aircraft carrying the sky divers or the pilot of that aircraft. 

All of the accidents included in this report have been assigned occurrence categories 

based on the taxonomy developed by the Commercial Aviation Safety Team/International 

Civil Aviation Organization (CAST/ICAO) Common Taxonomy Team (CICTT)4

. The 

author added a few categories to this taxonomy for non-transport accidents, and details on 

all categories can be found in Appendix A. The assignment of categories was performed 

by means of a computer program, based on the occurrence codes and causal factor codes 

in the NTSB database. During the assignment process, many of the more complicated 

accidents were reviewed by the author, and all of the fatal accidents for Part 121 and 

Scheduled Part 135 were reviewed by other NASA aviation safety systems analysis 

personnel. A particular accident might have been assigned multiple occurrence 

categories. 

One CICTT specification was not followed; this was with regard to loss of control when 

a system/component failure/malfunction rendered the aircraft uncontrollable. The CICTT 

taxonomy states that the loss of control should not be considered as a separate category in 

these cases. However, this analysis retained the loss of control category in all 

circumstances, regardless of malfunctions, in order to capture all of the loss of control 

including those that followed system/component failure/malfunction or other 

circumstances (incapacitation, weather) that might have rendered the aircraft 

uncontrollable.

The incident data were not categorized using the occurrence taxonomy. A single incident 

category was assigned to each incident to describe the primary occurrence. For example, 

if a system/component failure or malfunction occurred, the incident was classified 

according to the system of the malfunction, regardless of any consequences (e.g., loss of 

control, gear up landing, runway excursion, etc.). Details regarding the incident 

classifications are available in another paper5

. For the purposes of this analysis, the 

CICTT categories were mapped to the incident categories without additional review of 

the specific incident.

In 2008, the FAA revised the amount of data recorded for each incident, making the 

database even less informative. Some of the data fields are now blank for the most recent 

incidents. One of those fields was previously used to determine which of the Part 135 

flights were scheduled and which were non-scheduled. As a result, it is not possible to 

present incident data separately for scheduled versus non-scheduled Part 135 among 

incidents later than 2007. For most of this report, the incident data are presented for all 

Part 135 combined, whereas the Part 135 accident data are separated for scheduled versus 

non-scheduled. The lone exception is Table 2, in which the incident data were restricted 

to 2001-2007 in order to present those results separately.

4

 CAST/ICAO Common Taxonomy Team, “Aviation Occurrence Categories Definitions and Usage Notes, 

April 2011 (4.1.5) 

http://www.intlaviationstandards.org/Documents/CICTTOccurrenceCategoryDefinitions.pdf. 5

 Evans, JK, “A Description of Aviation Incidents During the Years 1985-2006”; March 2009. 

4
Results and Discussion 

Figure 1 shows the accident rate (per 1 million flight hours) over time for each of the 

three flight operation categories. Data for total flight hours per year were obtained from 

tables published by the NTSB, which they based on data from the FAA6

. The lowest 

accident rates continue to be in Part 121 (large transports), while the highest rates are in 

Part 91 (general aviation). The greatest rate of decline during this ten-year time period 

was in Non-Scheduled Part 135 (On-Demand Air Taxis) while the greatest variation was 

in Scheduled Part 135 (Commuter Airlines). In general, these statements are also true of 

the fatal accident rate (see Figure 2) and the incident rate (see Figure 3).

Figure 1. Accident Rate in Three Categories of Flight Operations (2001-2010). 

Figure 2. Fatal Accident Rate in Three Categories of Flight Operations (2001-2010). 

6

 Tables 5, 8 and 9. http://www.ntsb.gov/data/aviation_stats.html 

5
Figure 3. Incident Rate in Three Categories of Flight Operations (2001-2010). 

The reader is reminded that the incident data were combined for scheduled and nonscheduled Part 135 in 2008-2010. 

Although there is some indication of decline in both the total accident rate and fatal 

accident rate in every flight operations category, it is disturbing that the rates have 

remained so much higher in Part 135 and Part 91 relative to Part 121. 

The frequencies for each CICTT occurrence category within each flight operations 

category are shown in a series of five large tables in Appendix B. The specifics of these 

tables are as follows: 

Table B-1 – Total accidents 

Table B-2 – Total injuries (fatal, serious or minor) 

Table B-3 – Fatal accidents 

Table B-4 – Total fatalities 

Table B-5 – Total incidents 

The total number of accidents, incidents or injuries in a particular flight operations 

category also is provided in the tables. All of the percentages are based on these totals 

within the same category of flight operations. The reader is reminded that a particular 

accident might be assigned multiple occurrence categories. The additional categories that 

are not part of the official CICTT taxonomy are denoted with an asterisk (*) and these are 

provided for informational purposes only. Although the tables are organized by outcome 

(accident, incident or injury) the discussion below is organized by flight operation. The 

top few occurrence categories within each flight operation were selected from each table. 

The actual number of categories selected varies among tables and flight operation, but in 

each case a clear demarcation in percentages exists to distinguish those selected from 

those not selected. Charts showing the frequency of total accidents and fatal accidents for 

each category of flight operations are in Appendix C. 

6
Part 121

Among Part 121 accidents, the only occurrence categories assigned to more than ten 

percent of the accidents were turbulence encounters (27%), ground handling (24%) and 

ground collisions (12%). In terms of total injuries, the largest percentages were claimed 

by post-impact fires (35%), in-flight loss of control (28%), abrupt maneuvering (22%), 

security (20%) and turbulence encounters (19%). The occurrence categories responsible 

for the largest percentage of fatal accidents were ground handling (29%), post-impact 

fires (24%), in-flight loss of control (24%) and security (19%). The largest percentages of 

total fatalities were claimed by post-impact fires (57%), in-flight loss of control (51%), 

the terrorist attacks of 9/11 (38%) and abrupt maneuvering (38%). Among Part 121 

incidents, the only categories assigned to more than five percent of incidents were nonpowerplant system/component failures (41%), powerplant system/component failures 

(13%) and ground handling (13%). 

In summary, the following occurrence categories contributed the most to the overall 

safety risk in Part 121: abrupt maneuver, post-impact fires, ground collisions, ground 

handling, in-flight loss of control, non-powerplant system/component failures, 

powerplant system/component failures, security and turbulence encounters. 

Scheduled Part 135 

The categories assigned to at least fifteen percent of the Scheduled Part 135 accidents 

were runway excursion (19%), in-flight loss of control (15%) and abnormal runway 

contact (15%). The occurrence categories with more than fifteen percent of the injuries 

were in-flight loss of control (33%), powerplant system/component failures (25%), CFIT 

(19%) and icing (17%). The only category with more than one fatal event was in-flight 

loss of control (3 events), and the categories with the highest levels of fatalities were inflight loss of control (88%), icing (59%) and ground handling (18%). Among Part 135 

incidents, the only categories assigned to more than ten percent of incidents were nonpowerplant system/component failures (41%) and powerplant system/component failures 

(12%). 

In summary, the following occurrence categories made the largest contribution to the 

overall safety risk in Scheduled Part 135: abnormal runway contact, CFIT, ground 

handling, icing, in-flight loss of control, runway excursion, powerplant 

system/component failures and non-powerplant system/component failures. 

Non-Scheduled Part 135 

The top five categories in Non-Scheduled Part 135 accidents were in-flight loss of control 

(17%), runway excursion (16%), non-powerplant system/component failures (15%), postimpact fires (12%) and abnormal runway contact (12%). The occurrence categories 

responsible for more than fifteen percent of the injuries were in-flight loss of control 

7
(31%), post-impact fires (27%) and CFIT (22%). Similarly, the top three categories in 

terms of both fatal events and fatalities were in-flight loss of control (41% of fatal events 

and 39% of fatalities), post-impact fires (37% of fatal events and 32% of fatalities) and 

CFIT (31% of fatal events and 32% of fatalities). The only categories responsible for 

more than ten percent of Part 135 incidents were non-powerplant system/component 

failures (41%) and powerplant system/component failures (12%). 

In summary, the following occurrence categories made the largest contribution to the 

overall safety risk in Non-Scheduled Part 135: abnormal runway contact, CFIT, postimpact fires, in-flight loss of control, runway excursion, powerplant system/component 

failures and non-powerplant system/component failures. 

Part 91 

The top five categories in Part 91 accidents were runway excursion (21%), in-flight loss 

of control (20%), on-ground loss of control (16%), abnormal runway contact (14%) and 

fuel related loss of engine power (11%). The categories with more than twelve percent of 

total injuries were in-flight loss of control (41%), post-impact fires (24%) and fuel related 

loss of engine power (14%). In terms of both fatal events and fatalities, the top five 

categories were in-flight loss of control (57% of fatal events and 58% of fatalities), postimpact fires (37% and 38%), low altitude operations (15% and 14%), CFIT (13% of both 

fatal events and fatalities) and unintended flight in IMC (11% of both fatal events and 

fatalities). The top four categories in Part 91 incidents were abnormal runway contact 

(27%), non-powerplant system/component failures (26%), runway excursion (10%) and 

powerplant system/component failures (9%). 

In summary, the following occurrence categories made the largest contribution to the 

overall safety risk in Part 91: abnormal runway contact, CFIT, post-impact fires, low 

altitude operations, in-flight loss of control, on-ground loss of control, fuel related loss of 

engine power, runway excursion, powerplant system/component failures, non-powerplant 

system/component failures and unintended flight in IMC.

Table 1 summarizes the impact of each of the occurrence categories that were found to be 

top contributors to the safety risk within each flight operations category. The absence of 

summary statistics for a particular occurrence category within a particular flight 

operations category should not lead the reader to conclude that there were no events 

within that operation category that were assigned to that occurrence category. Rather, the 

number of events assigned to that occurrence category was not large enough for it to be 

considered a major contributor to the safety risk. The following abbreviations were used: 

x TA - Total Accidents 

x TAI - Total Accident Injuries 

x FA - Fatal Accidents 

x TF - Total Fatalities 

x TI - Total Incidents 

8
Table 1. Most Frequently Cited CICTT Occurrence Categories (2001-2010) 

CICTT Occurrence 

Category Part 121 ScheduledPart 135 

NonScheduled

Part 135 

Part 91 

Abrupt Maneuver 22% of TAI 

38% of TF 

Abnormal Runway Contact 15% of TA 12% of TA 14% of TA 

27% of TI 

Controlled Flight Into 

Terrain 19% of TAI 

22% of TAI 

31% of FA

32% of TF 

13% of FA 

13% of TF 

Fire – Post Impact 

35% of TAI 

24% of FA 

57% of TF 

12% of TA 

27% of TAI 

37% of FA 

32% of TF 

24% of TAI 

37% of FA 

38% of TF 

Ground Collision 12% of TA 

Ground Handling 

24% of TA 

29% of FA 

13% of TI 

18% of TF 

Icing 17% of TAI 

59% of TF 

Low Altitude Maneuvering 15% of FA 

14% of TF 

Loss of Control – On 

Ground/Water 16% of TA 

Loss of Control – In Flight 

28% of TAI 

24% of FA 

51% of TF 

15% of TA 

33% of TAI 

75% of FA 

88% of TF 

17% of TA 

31% of TAI 

41% of FA 

39% of TF 

20% of TA 

41% of TAI 

57% of FA 

58% of TF 

Fuel Related Loss of 

Engine Power 

11% of TA 

14% of TAI 

Runway Excursion 19% of TA 16% of TA 21% of TA 

10% of TI 

SCF – Powerplant 13% of TI 25% of TAI 

12% of TI 12% of TI 9% of TI 

SCF – Non Powerplant 41% of TI 41% of TI 15% of TA 

41% of TI 26% of TI 

Security Related 

20% of TAI 

19% of FA 

38% of TF 

Turbulence Encounter 27% of TA 

19% of TAI 

Unintended Flight in IMC 11% of FA 

11% of TF 

9
One accident (AA587 on 12NOV01) with abrupt maneuvering (which led to the failure 

of the vertical stabilizer and a total loss of control) was responsible for 38% of the Part 

121 fatalities in this time period. This was the same number of people killed earlier that 

month in four aircraft on 9/11. It was only one accident, but it highlights the need for 

stringent and comprehensive flight training. 

Abnormal runway contact is a major contributor to the safety risk in Part 135 and Part 91 

based mostly on the percentage of total accidents (12% and 15%), but it is also a minor 

contributor for Part 121 (10% of total accidents). 

Controlled flight into terrain (CFIT) is a major contributor to the safety risk for all 

operations except Part 121. Safety enhancements such as EGPWS (Enhanced Ground 

Proximity Warning System) have been invaluable. Compared with a similar analysis for 

1997-2006 data7

, it appears the risk may be shrinking among Scheduled Part 135, but 

rising among Non-Scheduled Part 135. 

Post-impact fire is a major contributor for all operations except Scheduled Part 135. 

24-37% of fatal accidents and 32-57% of all fatalities occur in accidents with post-impact 

fires. 

Ground collision accidents accounted for twelve percent of Part 121 accidents and ten 

percent of Scheduled Part 135 accidents, but outside of Part 91 operations did not result 

in a fatality during this time period. 

Ground handling accidents are most common in Part 121. Five of the six Part 121 

ground handling fatal accidents resulted in only one fatality. 

Icing affects mostly Scheduled Part 135 flights. It is interesting to note that, based on a 

review of the accident database, 85 percent of the Scheduled Part 135 accidents occurred 

in Alaska (41 of 48), compared with 8 percent of the other flight operation categories 

(941/11680). Similarly, two of the four fatal accidents in Scheduled Part 135 occurred in 

Alaska, compared with 4 percent of the other flight operations (81/2121).

In-flight loss of control is an important part of the safety risk due more to the number of 

injuries, especially fatal injuries, than to the number of accidents. This category is one of 

three to have a major impact on all four flight operations in this time period. In-flight loss 

of control is so likely to result in injury or substantial aircraft damage that it is rarely seen 

among incidents. When an incident does include in-flight loss of control, the loss of 

control is nearly always preceded by system/component failure/malfunction or severe 

weather, and control is regained prior to a collision. 

7

 Jones SM, Reveley, MS, Withrow C, Evans, JK, Barr LC, Leone, K. “Systems Analysis of NASA 

Aviation Safety Program: Final Report”; October 2013 

10
Runway excursion accounts for 16-21 percent of accidents outside Part 121. However, 

runway excursion in Part 121 results in higher percentages of injuries (12%), fatal 

accidents (10%) and fatalities (7%) than are seen in Part 135 or Part 91. 

The major contribution of both powerplant and non-powerplant system/component 

failures/malfunctions to the safety risk is in terms of incidents. However, 25% of all 

injuries in Scheduled Part 135 accidents are attributed to powerplant SCFM and 15% of 

Non-Scheduled Part 135 accidents are attributed to non-powerplant SCFM. 

The security occurrence category is a major contributor to the safety risk only in Part 121 

operations.

Similarly, encounters with turbulence account for less than seven percent of any kind of 

accidents or injuries in flight operations other than Part 121. However, in Part 121 flights, 

turbulence is responsible for 27% of accidents and 19% of injuries, making it the single 

largest cause of accidents in this operations category. 

Unintended flight in IMC conditions was added to the CAST/ICAO taxonomy in May of 

2011. This type of accident is primarily an issue for Part 91 flights, accounting for 11% 

of fatal accidents and 11% of fatalities. 

These seventeen accident categories collectively were assigned to 88% of the accidents 

during 2001-2010 (Part 121: 89%; Scheduled Part 135: 83%; Non-Scheduled Part 135: 

84%; Part 91:88%); 93% of the fatal accidents (Part 121: 90%; Scheduled Part 135: 

100%; Non-Scheduled Part 135: 88%; Part 91:93%) and 88% of incidents (Part 121: 

81%; Part 135: 86%; Part 91: 89%).

Since several occurrence categories are major contributors to the safety risk for only one 

flight operations category, Table 2 shows the percentage of accidents or incidents that 

have been assigned to the set of occurrence categories specific to that category of flight 

operations. For the incidents only, Part 135 operations were restricted to 2001-2007, in 

order to maintain the separation between Scheduled and Non-Scheduled flights. 

Table 2. Number of Events Assigned to At Least One of the Most Frequent CICTT 

Occurrence Categories Within Each Category of Flight Operations (2001-2010) 

Type of Outcome Part 121 Scheduled

Part 135 

Non-Scheduled

Part 135 Part 91 

Total Accidents 289 (77.5%) 31 (64.6%) 282 (66.2%) 9222 (84.8%) 

Total Injuries 1151 (87.7%) 50 (78.1%) 332 (74.8%) 7183 (86.0%) 

Fatal Accidents 17 (81.0%) 4 (100.%) 76 (80.0%) 1833 (91.4%) 

Fatal Injuries 692 (99.3%) 17 (100.%) 178 (77.1%) 3522 (89.2%) 

Incidents * 1920 (75.7%) 79 (79.0%) 442 (67.6%) 8455 (80.5%) 

*For this table only, Part 135 incident data was restricted to 2001-2007. 

11
Conclusions

This analysis has determined four groups of occurrence categories (with between seven 

and eleven categories per group) that contribute greatly to the safety risk within each of 

the flight operations categories. Collectively, the occurrence categories in these groups 

represent 88% of accidents and 88% of incidents. Individually, these groups represent 65-

85% of accidents and 68-81% of incidents. In general, the occurrence categories that are 

most important to the safety risk across all categories of flight operations are in-flight loss 

of control and system/component failure/malfunction. 

12
Appendix A 

Aviation Occurrence Categories 

13
The CAST/ICAO Common Taxonomy Team (CICTT) was jointly chartered by the 

International Civil Aviation Organization (ICAO) and the Commercial Aviation Safety 

Team (CAST), and was charged with developing common taxonomies and definitions for 

aviation accident and incident reporting systems (for additional information see 

http://www.intlaviationstandards.org/). The occurrence categories are listed below, with 

brief descriptions of each. The information is taken from a document dated October 2008. 

CICTT Categories 

Abnormal Runway Contact (ARC): Any takeoff or landing involving abnormal contact 

with the runway or landing surface. Included are hard/heavy landings, long/fast landings, 

crabbed landings, nose wheel first touchdowns, tail strikes, wing/nacelle strikes and gear 

up landings. 

Abrupt Maneuver (AMAN): The intentional abrupt maneuvering of the aircraft (in-flight 

or on-ground) by the flight crew to avoid a collision with terrain, objects, weather or 

other aircraft. 

Aerodrome (ADRM): Occurrences involved aerodrome design, service or functionality 

issues. The aerodrome includes runways, taxiways, ramp areas, parking areas, buildings 

and structures, lighting, signage Crash/Fire/Rescue (CFR) services. 

ATM/CNS (ATM): Occurrences involving air traffic management (ATM) or 

communication, navigation or surveillance (CNS) service issues. 

Bird Strike (BIRD): Occurrences involving collisions or near collisions with bird(s) or 

wildlife. 

Cabin Safety Events (CABIN): Includes significant events in the passenger cabin, related 

to carry-on baggage, supplemental oxygen, missing/non-operational emergency 

equipment, the inadvertent deployment of emergency equipment, and the medical 

emergency (not caused by turbulence encounters) of persons other than the flight crew or 

medical evacuation patients. 

Collision with Obstacle(s) during Takeoff and Landing (CTOL): A collision with an 

object or obstacle during airborne phases of take-off or landing. 

Controlled Flight Into or toward Terrain (CFIT): In-flight collision or near collision with 

terrain, water or obstacle without indication of loss of control. Excludes intentional low 

altitude operations, intentional flight into terrain and runway undershoot/overshoot. 

Evacuation (EVAC): Occurrences including one or more of the following: an 

unnecessary evacuation was performed, person(s) were injured during the evacuation, 

evacuation equipment failed to perform as required, or the evacuation was a factor in the 

outcome. 

14
External Load Related Occurrences (EXTL): Occurences during or as a result of external 

load or external cargo operations. Includes cases where external load or the load lifting 

equipment contacts terrain, water surface or objects. 

Fire/Smoke Non-Impact (FI-NI): Fire or smoke in the aircraft (in-flight or on-ground) 

which was not the result of an impact. 

Fire/Smoke Impact (FI-POST): Fire or smoke resulting from impact. 

Fuel Related (FUEL): One or more powerplants experienced reduced or no power output 

due to fuel exhaustion (no usable fuel on board), fuel starvation (usable fuel is not 

available to the engine), fuel contamination (by water, sand, dirt, bugs) or wrong fuel, or 

carburetor and/or induction icing. 

Glider Towing Related Events (GTOW): Premature release, inadvertent release or nonrelease during towing, entangling with towing, cable, loss of control, or impact into 

towing aircraft/winch. 

Ground Handling (RAMP): Occurrences during (or as a result of) ground operations, 

including preflight configuration errors that lead to subsequent events (such as 

improperly latched doors, pitot tube contamination, or weight/balance issues). 

Ground Collision (GCOL): Collision with an aircraft, person, animal, ground vehicle, 

building, etc., while taxiing to or from the runway in use. 

Icing (ICE): The accumulation of snow, ice, freezing rain or frost on aircraft surfaces to 

the extent that aircraft control or performance is adversely affected. 

Loss of Control – Ground (LOC-G): Loss of aircraft control while the aircraft is on the 

ground, which may result from a contaminated runway, evasive action due to a runway 

incursion, or the failure or malfunction of a system or component. 

Loss of Control – In flight (LOC-I): Loss of aircraft control while in flight; may occur in 

Instrument Meteorological Conditions (IMC) or Visual Meteorological Conditions 

(VMC).

Loss of Lifting Conditions En-Route: (LOLI): Landing en-route due to loss of lifting 

conditions. Applicable only to aircraft that rely on static lift to maintain or increase flight 

attitude, namely sailplanes, gliders, hang gliders, and paragliders, balloons and airships.

Low Altitude Operations (LALT): Collision or near collision with 

terrain/objects/obstacles while intentionally operating near the surface (excludes landing 

and takeoff phases). Includes aerobatics, sight-seeing, aerial photography, aerial 

application, scud running, and flying in close proximity to mountains or box canyons 

where the aircraft aerodynamic capability is not sufficient to avoid impact. 

15
Airprox/TCAS Alert/Loss of Separation/Near Mid-Air Collision/Mid-Air Collision 

(MAC): Airprox, TCAS alerts and loss of separation, as well as near collisions or 

collisions between aircraft in flight. 

Other (OTHER): Any occurrence not covered under another category. 

Runway Excursion (RE): A veer off the side or overrun off the end of the runway. 

Runway Incursion – Animal (RI-A): Collision with, risk of collision with, or evasive 

action taken by an aircraft to avoid an animal (other than birds) on the runway in use. 

Runway Incursion – Vehicle, Aircraft or Person (RI-VAP): The incorrect presence of an 

aircraft, vehicle or person on the protected area of a surface designated for takeoffs or 

landings.

Security Related (SEC): Criminal or security related acts such as hijacking, aircraft theft, 

flight control interference, sabotage or suicide. 

System/Component Failure or Malfunction – Non-powerplant (SCF-NP): Failure or 

malfunction of an aircraft system or component other than the powerplant. 

System/Component Failure or Malfunction – Powerplant (SCF-PP): Failure or 

malfunction of an aircraft system or component related to the powerplant. 

Turbulence Encounter (TURB): In flight encounter with turbulence; includes clear-air or 

cloud turbulence, mountain wave and wake vortex. 

Unintended Flight in Instrument Meteorological Conditions (UIMC): Applicable if the 

pilot was flying according to Visual Flight Rules (VFR), and by any reason found oneself 

inadvertently in IMC. Only to be used if pilot not qualified to fly in IMC and/or aircraft 

not equipped to fly in IMC, and only in the case of a loss of visual references. 

Undershoot/Overshoot (USOS): A touchdown off the runway surface but in close 

proximity to the runway. Excludes off-airport emergency landings. 

Unknown or Undetermined (UNK): Insufficient information exists to categorize the 

accident; includes missing aircraft. 

Windshear or Thunderstorm (WSTRW): Flight into windshear or thunderstorm; includes 

hail and heavy rain. 

Additional Categories 

Many of the following categories were added in order to completely capture the event 

sequence. An emergency landing is required in most cases of System/Component 

16
Failure/Malfunction and Loss of Engine Power, and may be performed after an encounter 

with adverse weather; this landing often is not without further incident. Control of the 

aircraft may be lost, hard or bounced landings may occur, terrain unsuitable for a proper 

landing may be encountered, the aircraft may collide with power lines, fences or ground 

vehicles during an off-airport landing, the aircraft may be unable to avoid rising terrain 

due to degraded performance. The single category of “Loss of Engine Power” is not 

sufficient to explain why the aircraft was destroyed. 

Several categories (collisions with terrain or objects and loss of control) were further 

subdivided by general phase of flight (ground, takeoff, in flight, approach/landing) 

because either the root cause or the consequences of the occurrence differ by phase of 

flight.

Collision with Object – Precautionary Landing (CWO-PL): A collision with an object or 

obstacle occurred during a precautionary landing approach. CFIT is not an appropriate 

category in these cases because a system/component failure/malfunction or nonmechanical loss of engine power necessitated the landing.

Collision with Terrain – Precautionary Landing (CWT-PL): A collision with terrain 

occurred during a precautionary landing approach. CFIT is not an appropriate category in 

these cases because a system/component failure/malfunction or non-mechanical loss of 

engine power necessitated the landing. This code was also used in cases where the pilot 

“ditched” the aircraft in water. 

Encounter with Terrain – Precautionary Landing (EWT-PL): An encounter with terrain 

occurred on the ground away from an airport environment during a precautionary 

landing, causing damage to the aircraft. The difference between this category and CWTPL is primarily the force with which the aircraft strikes the ground at touchdown. An 

encounter with terrain involves a normal touchdown, with rough terrain encountered 

during the landing roll. Included here are intentional gear-up off-airport landings. 

Pilot Incapacitation or Severe Impairment (INCAP): Pilot became incapacitated (due to 

illness or fatigue) or severely impaired (due to illness, alcohol or illegal drugs). Does not 

include minor impairment caused by fatigue or the use of unapproved prescription 

medications. 

Loss of Engine Power – Fuel Related (PL-FUEL): Loss of engine power due to fuel 

exhaustion (no usable fuel on board), fuel starvation (usable fuel is not available to the 

engine), fuel contamination (by water, sand, dirt, bugs) or wrong fuel, or carburetor 

and/or induction icing (see FUEL above). 

Loss of Engine Power – Other Reasons (PL-OTHER): Loss of engine power due to other 

non-mechanical reasons. Reasons include foreign object damage (e.g. bird strikes), ice 

ingestion, improper simulated engine out procedures, other improper procedures. 

17
Loss of Engine Power – Unknown Reasons (PL-UNK): Loss of engine power occurred 

but the exact cause was undetermined. 

SCF-SLE: Structural failure due to exceeding the designed stress limits of the aircraft, 

most often resulting from loss of control, from forces associated with severe weather or 

from pilot actions such as excessive airspeed or abrupt maneuvering. 

18
Appendix B 

Tables of the Frequencies of Total Accidents, Total Injuries, 

 Fatal Accidents, Fatal Injuries and Incidents 

by Aviation Occurrence Categories 

19
Table B-1. Number of Accidents by CICTT Occurrence Category (2001-2010) 

CICTT Occurrence 

Category Part 121 ScheduledPart 135 

NonScheduled

Part 135 

Part 91 

Total Accidents 373 48 426 10881 

Abrupt Maneuver 12 ( 3.2%) 0 ( 0.0%) 2 ( 0.5%) 53 ( 0.5%) 

Abnormal Runway Contact 36 ( 9.7%) 7 (14.6%) 49 (11.5%) 1549 (14.2%) 

Aerodrome 3 ( 0.8%) 2 ( 4.2%) 15 ( 3.5%) 122 ( 1.1%) 

Air Traffic Management 9 ( 2.4%) 2 ( 4.2%) 6 ( 1.4%) 64 ( 0.6%) 

Bird Strikes 15 ( 4.0%) 2 ( 4.2%) 6 ( 1.4%) 42 ( 0.4%) 

Cabin Safety or Pilot 

Incapacitation 4 ( 1.1%) 0 ( 0.0%) 4 ( 0.9%) 134 ( 1.2%) 

Controlled Flight Into Terrain 2 ( 0.5%) 3 ( 6.3%) 42 ( 9.8%) 346 ( 3.2%) 

Collision with Object – 

Takeoff or Landing 1 ( 0.3%) 2 ( 4.2%) 14 ( 3.3%) 384 ( 3.5%) 

Collision with Object – 

Precautionary Landing * 16 ( 3.7%) 1019 ( 9.4%) 

Collision with Terrain – 

Precautionary Landing * 2 ( 0.5%) 1 ( 2.1%) 18 ( 4.2%) 449 ( 4.1%) 

Encounter with Terrain – 

Precautionary Landing * 1 ( 0.3%) 2 ( 4.2%) 12 ( 2.8%) 658 ( 6.0%) 

Evacuation 17 ( 4.6%) 1 ( 2.1%) 1 ( 0.3%) 

Fire – Non-Impact 11 ( 2.9%) 2 ( 4.2%) 8 ( 1.9%) 113 ( 1.0%) 

Fire – Post Impact 12 ( 3.2%) 2 ( 4.2%) 51 (12.0%) 990 ( 9.1%) 

Ground Collision 46 (12.3%) 5 (10.4%) 26 ( 6.1%) 244 ( 2.2%) 

Ground Handling or PreFlight 88 (23.6%) 3 ( 6.3%) 24 ( 5.6%) 259 ( 2.4%) 

Icing 3 ( 0.8%) 3 ( 6.3%) 23 ( 5.4%) 117 ( 1.1%) 

Low Altitude Operations 11 ( 2.6%) 520 ( 4.8%) 

Loss of Control – In Flight 8 ( 2.1%) 7 (14.6%) 73 (17.1%) 2129 (19.6%) 

Loss of Control – On Ground 4 ( 8.3%) 35 ( 8.5%) 1711 (15.7%) 

Mid Air Collision 1 ( 0.3%) 5 ( 1.2%) 114 ( 1.0%) 

Power Loss – Fuel 1 ( 0.3%) 1 ( 2.1%) 23 ( 5.4%) 1235 (11.4%) 

Power Loss – Other Reason * 71 ( 0.7%) 

Power Loss – Unknown 

Reason * 18 ( 4.2%) 702 ( 6.5%) 

Runway Excursion 27 ( 7.2%) 9 (18.8%) 69 (16.2%) 2327 (21.4%) 

Runway Incursion (Animal, 

Vehicle, Aircraft or Person) 3 ( 0.8%) 5 ( 1.2%) 107 ( 1.0%) 

SCF – Powerplant 9 ( 2.4%) 4 ( 8.3%) 22 ( 5.2%) 643 ( 5.9%) 

SCF – Non Powerplant 29 ( 7.8%) 4 ( 8.3%) 63 (14.8%) 784 ( 7.2%) 

SCF – Stress Limits 

Exceeded* 3 ( 0.7%) 81 ( 0.7%) 

Security Related 4 ( 1.1%) 27 ( 0.2%) 

Turbulence Encounter 101 (27.1%) 2 ( 4.2%) 3 ( 0.7%) 68 ( 0.6%) 

Thunderstorm or Windshear 2 ( 0.5%) 6 ( 1.4%) 130 ( 1.2%) 

Undershoot or Overshoot 1 ( 0.3%) 1 ( 2.1%) 9 ( 2.1%) 210 ( 1.9%) 

Unintended Flight in IMC 2 ( 4.2%) 11 ( 2.6%) 259 ( 2.4%) 

Other 3 ( 0.8%) 9 ( 2.1%) 53 ( 0.5%) 

Unknown or Undetermined 2 ( 0.5%) 10 ( 2.3%) 72 ( 0.7%) 

20
Table B-2. Number of Injuries in Accidents by CICTT Occurrence Category (2001-2010) 

CICTT Occurrence 

Category Part 121 ScheduledPart 135 

NonScheduled

Part 135 

Part 91 

Total Injuries 1312 64 444 8349 

Abrupt Maneuver 288 (22.0%) 1 ( 0.2%) 67 ( 0.8%) 

Abnormal Runway Contact 54 ( 4.1%) 0 ( 0.0%) 19 ( 4.3%) 322 ( 3.9%) 

Aerodrome 0 ( 0.0%) 2 ( 3.1%) 1 ( 0.2%) 19 ( 0.2%) 

Air Traffic Management 5 ( 0.4%) 1 ( 1.6%) 6 ( 1.4%) 74 ( 0.9%) 

Bird Strikes 6 ( 0.5%) 0 ( 0.0%) 3 ( 0.7%) 14 ( 0.2%) 

Cabin Safety or Pilot 

Incapacitation 4 ( 0.3%) 5 ( 1.1%) 202 ( 2.4%) 

Controlled Flight Into Terrain 18 ( 1.4%) 12 (18.8%) 98 (22.1%) 665 ( 8.0%) 

Collision with Object – 

Takeoff or Landing 0 ( 0.0%) 9 (14.1%) 12 ( 2.7%) 360 ( 4.3%) 

Collision with Object – 

Precautionary Landing * 24 ( 5.4%) 1026 (12.2%) 

Collision with Terrain – 

Precautionary Landing * 13 ( 1.0%) 8 (12.5%) 25 ( 5.6%) 519 ( 6.2%) 

Encounter with Terrain – 

Precautionary Landing * 5 ( 0.4%) 6 ( 9.4%) 8 ( 1.8%) 378 ( 4.5%) 

Evacuation 106 ( 8.1%) 8 (12.5%) 6 ( 1.4%) 

Fire – Non-Impact 34 ( 2.6%) 0 ( 0.0%) 4 ( 0.9%) 73 ( 0.9%) 

Fire – Post Impact 461 (35.1%) 3 ( 4.7%) 118 (26.6%) 1985 (23.8%) 

Ground Collision 19 ( 1.4%) 1 ( 1.6%) 1 ( 0.2%) 28 ( 0.3%) 

Ground Handling or PreFlight 66 ( 5.0%) 3 ( 4.7%) 39 ( 8.8%) 338 ( 4.0%) 

Icing 52 ( 4.0%) 11 (17.2%) 27 ( 6.1%) 172 ( 2.1%) 

Low Altitude Operations 25 ( 5.6%) 816 ( 9.8%) 

Loss of Control – In Flight 361 (27.5%) 21 (32.8%) 139 (31.3%) 3459 (41.4%) 

Loss of Control – On Ground 0 ( 0.0%) 21 ( 4.7%) 413 ( 4.9%) 

Mid Air Collision 0 ( 0.0%) 2 ( 0.5%) 286 ( 3.4%) 

Power Loss – Fuel 2 ( 0.2%) 0 ( 0.0%) 39 ( 8.8%) 1174 (14.1%) 

Power Loss – Other Reason * 73 ( 0.9%) 

Power Loss – Unknown 

Reason * 18 ( 4.1%) 703 ( 8.4%) 

Runway Excursion 162 (12.3%) 3 ( 4.7%) 42 ( 9.5%) 560 ( 6.7%) 

Runway Incursion (Animal, 

Vehicle, Aircraft or Person) 0 ( 0.0%) 2 ( 0.5%) 16 ( 0.2%) 

SCF – Powerplant 28 ( 2.1%) 16 (25.0%) 23 ( 5.2%) 575 ( 6.9%) 

SCF – Non Powerplant 94 ( 7.2%) 0 ( 0.0%) 43 ( 9.7%) 284 ( 3.4%) 

SCF – Stress Limit Exceeded * 3 ( 0.7%) 196 ( 2.3%) 

Security Related 265 (20.2%) 29 ( 0.3%) 

Turbulence Encounter 251 (19.1%) 4 ( 6.3%) 8 ( 1.8%) 83 ( 1.0%) 

Thunderstorm or Windshear 0 ( 0.0%) 9 ( 2.0%) 188 ( 2.3%) 

Undershoot or Overshoot 0 ( 0.0%) 0 ( 0.0%) 7 ( 1.6%) 82 ( 1.0%) 

Unintended Flight in IMC 4 ( 6.3%) 19 ( 4.3%) 515 ( 6.2%) 

Other 0 ( 0.0%) 3 ( 0.7%) 23 ( 0.3%) 

Unknown or Undetermined 4 ( 0.3%) 26 ( 5.9%) 130 ( 1.6%) 

21
Table B-3. Number of Fatal Accidents by CICTT Occurrence Category (2001-2010) 

CICTT Occurrence 

Category Part 121 ScheduledPart 135 

NonScheduled

Part 135 

Part 91 

Total Fatal Accidents 21 4 95 2005 

Abrupt Maneuver 1 ( 4.8%) 27 ( 1.3%) 

Abnormal Runway Contact 1 ( 1.1%) 26 ( 1.3%) 

Aerodrome 1 ( 0.1%) 

Air Traffic Management 2 ( 2.1%) 33 ( 1.6%) 

Bird Strikes 2 ( 0.1%) 

Cabin Safety or Pilot 

Incapacitation 4 ( 4.2%) 101 ( 5.0%) 

Controlled Flight Into Terrain 1 ( 4.8%) 29 (30.5%) 265 (13.2%) 

Collision with Object – 

Takeoff or Landing 1 ( 4.1%) 69 ( 3.4%) 

Collision with Object – 

Precautionary Landing * 2 ( 2.1%) 121 ( 6.0%) 

Collision with Terrain – 

Precautionary Landing * 2 ( 9.5%) 1 (25.0%) 3 ( 3.2%) 75 ( 3.7%) 

Encounter with Terrain – 

Precautionary Landing * 7 ( 0.3%) 

Evacuation 1 (25.0%) 

Fire – Non-Impact 2 ( 9.5%) 14 ( 0.7%) 

Fire – Post Impact 5 (23.8%) 35 (36.8%) 739 (36.9%) 

Ground Collision 3 ( 0.1%) 

Ground Handling or PreFlight 6 (28.6%) 1 (25.0%) 5 ( 5.3%) 66 ( 3.3%) 

Icing 1 ( 4.8%) 1 (25.0%) 9 ( 9.5%) 58 ( 2.9%) 

Low Altitude Operations 7 ( 7.4%) 309 (15.4%) 

Loss of Control – In Flight 5 (23.8%) 3 (75.0%) 39 (41.1%) 1149 (57.3%) 

Loss of Control – On Ground 1 ( 1.1%) 15 ( 0.7%) 

Mid Air Collision 1 ( 1.1%) 66 ( 3.3%) 

Power Loss – Fuel 1 ( 4.8%) 1 ( 1.1%) 145 ( 7.2%) 

Power Loss – Other Reason * 8 ( 0.4%) 

Power Loss – Unknown 

Reason * 4 ( 4.2%) 104 ( 5.2%) 

Runway Excursion 2 ( 9.5%) 2 ( 2.1%) 33 (1.6%) 

Runway Incursion (Animal, 

Vehicle, Aircraft or Person) 2 ( 0.1%) 

SCF – Powerplant 1 ( 4.8%) 1 (25.0%) 2 ( 2.1%) 92 ( 4.6%) 

SCF – Non Powerplant 2 ( 9.5%) 6 ( 6.3%) 70 ( 3.5%) 

SCF – Stress Limit Exceeded* 3 ( 3.2%) 79 ( 3.9%) 

Security Related 4 (19.0%) 16 ( 0.8%) 

Turbulence Encounter 2 ( 1.6%) 25 ( 1.2%) 

Thunderstorm or Windshear 2 ( 1.6%) 66 ( 3.3%) 

Undershoot or Overshoot 5 ( 0.2%) 

Unintended Flight in IMC 7 ( 7.4%) 212 (10.6%) 

Other 6 ( 0.3%) 

Unknown or Undetermined 2 ( 9.5%) 9 ( 9.5%) 61 ( 3.0%) 

22
Table B-4. Number of Fatalities by CICTT Occurrence Category (2001-2010) 

CICTT Occurrence 

Category Part 121 ScheduledPart 135 

NonScheduled

Part 135 

Part 91 

Total Fatalities 697 17 231 3948 

Abrupt Maneuver 265 (38.0%) 54 ( 1.4%) 

Abnormal Runway Contact 2 ( 0.9%) 38 ( 1.0%) 

Aerodrome 1 ( 0.1%) 

Air Traffic Management 3 ( 1.3%) 67 ( 1.7%) 

Bird Strikes 7 ( 0.2%) 

Cabin Safety or Pilot 

Incapacitation 5 ( 2.2%) 160 ( 4.1%) 

Controlled Flight Into Terrain 13 ( 1.9%) 73 (31.6%) 517 (13.1%) 

Collision with Object – 

Takeoff or Landing 8 ( 3.5%) 132 ( 3.3%) 

Collision with Object – 

Precautionary Landing * 2 ( 0.9%) 193 ( 4.9%) 

Collision with Terrain – 

Precautionary Landing * 3 ( 0.4%) 2 (11.8%) 3 ( 1.3%) 124 ( 3.1%) 

Encounter with Terrain – 

Precautionary Landing * 12 ( 0.3%) 

Evacuation 2 (11.8%) 

Fire – Non-Impact 22 ( 3.2%) 26 ( 0.7%) 

Fire – Post Impact 398 (57.1%) 74 (32.0%) 1509 (38.2%) 

Ground Collision 4 ( 0.1%) 

Ground Handling or PreFlight 26 ( 3.7%) 3 (17.6%) 15 ( 6.5%) 147 ( 3.7%) 

Icing 50 ( 7.2%) 10 (58.8%) 12 ( 5.2%) 123 ( 3.1%) 

Low Altitude Operations 22 ( 9.5%) 555 (14.1%) 

Loss of Control – In Flight 358 (51.4%) 15 (88.2%) 89 (38.5%) 2281 (57.8%) 

Loss of Control – On Ground 2 ( 0.9%) 18 ( 0.5%) 

Mid Air Collision 2 ( 0.9%) 248 ( 6.3%) 

Power Loss – Fuel 1 ( 0.1%) 1 ( 0.4%) 233 ( 5.9%) 

Power Loss – Other Reason * 11 ( 0.3%) 

Power Loss – Unknown 

Reason * 5 ( 2.2%) 187 ( 4.7%) 

Runway Excursion 50 ( 7.2%) 5 ( 2.2%) 55 ( 1.4%) 

Runway Incursion (Animal, 

Vehicle, Aircraft or Person) 2 ( 0.1%) 

SCF – Powerplant 2 ( 0.3%) 2 (11.8%) 8 ( 3.5%) 185 ( 4.7%) 

SCF – Non Powerplant 41 ( 5.9%) 19 ( 8.2%) 123 ( 3.1%) 

SCF – Stress Limits Exceeded 3 ( 1.3%) 195 ( 4.9%) 

Security Related 265 (38.0%) 20 ( 0.5%) 

Turbulence 3 ( 1.3%) 55 ( 1.4%) 

Thunderstorm or Windshear 2 ( 0.9%) 152 ( 3.9%) 

Undershoot or Overshoot 9 ( 0.2%) 

Unintended Flight in IMC 14 ( 6.1%) 438 (11.1%) 

Other 10 ( 0.3%) 

Unknown or Undetermined 3 ( 0.4%) 24 (10.4%) 152 ( 3.9%) 

23
Table B-5. Number of Incidents by CICTT Occurrence Category (2001-2010) 

CICTT Occurrence Category Part 121 

Scheduled and 

Non-Scheduled

Part 135 

Part 91 

Total Incidents 2537 1000 10508 

Abnormal Runway Contact 44 ( 1.7%) 77 ( 7.7%) 2796 (26.6%)

Aerodrome 27 ( 1.1%) 15 ( 1.5%) 121 ( 1.2%)

Bird Strikes 111 ( 4.4%) 27 ( 2.7%) 77 ( 0.7%)

Cabin Safety or Pilot Incapacitation 45 ( 1.8%) 3 ( 0.3%) 16 ( 0.2%)

Collision with Object – Takeoff or 

Landing 5 ( 0.2%) 15 ( 1.5%) 152 ( 1.4%)

Evacuation 32 ( 1.3%)

Fire – Non-Impact 91 ( 3.6%) 32 ( 3.2%) 112 ( 1.1%)

Ground Collision 46 ( 1.8%) 70 ( 7.0%) 433 ( 4.1%)

Ground Handling or Inadequate PreFlight 337 (13.3%) 78 ( 7.8%) 448 ( 4.3%)

Icing 2 ( 0.1%) 4 ( 0.4%) 18 ( 0.2%)

Low Altitude Operations 2 ( 0.2%) 19 ( 0.2%)

Loss of Control – On Ground 26 ( 1.0%) 16 ( 1.6%) 497 ( 4.7%)

Mid Air Collision 9 ( 0.4%) 2 ( 0.2%) 72 ( 0.7%) 

Power Loss – Fuel 15 ( 0.6%) 15 ( 1.5%) 479 ( 4.6%)

Power Loss – Other or Unknown 

Reason * 9 ( 0.9%) 173 ( 1.6%)

Runway Excursion 54 ( 2.1%) 60 ( 6.0%) 1002 ( 9.5%)

Runway Incursion (Animal, Vehicle, 

Aircraft or Person) 9 ( 0.4%) 1 ( 0.1%) 21 ( 0.2%)

SCF – Powerplant 339 (13.4%) 118 (11.8%) 920 ( 8.8%)

SCF – Non Powerplant 1048 (41.3%) 412 (41.2%) 2742 (26.1%)

Security Related 91 ( 3.6%) 3 ( 0.3%) 10 ( 0.1%)

Turbulence Encounter 59 ( 2.3%) 3 ( 0.3%) 13 ( 0.1%)

Thunderstorm or Windshear 18 ( 0.7%) 2 ( 0.2%) 10 ( 0.1%)

Undershoot or Overshoot 3 ( 0.1%) 5 ( 0.5%) 56 ( 0.5%)

Other 103 ( 4.1%) 25 ( 2.5%) 252 ( 2.4%)

Unknown or Undetermined 23 ( 0.9%) 6 ( 0.6%) 52 ( 0.5%)

24
Appendix C 

Charts of the Frequencies of Total Accidents and Fatal Accidents by 

Aviation Occurrence Categories 

25
Figure 4. Number of Accidents by CICTT Occurrence Category in Part 121 (2001-2010). 

Figure 5. Number of Fatal Accidents by CICTT Occurrence Category in Part 121 

(2001-2010).

26
Figure 6. Number of Accidents by CICTT Occurrence Category in Scheduled Part 135 

(2001-2010). 

Figure 7. Number of Fatal Accidents by CICTT Occurrence Category 

in Scheduled Part 135 (2001-2010). 

27
Figure 8. Number of Accidents by CICTT Occurrence Category 

in Non-Scheduled Part 135 (2001-2010). 

Figure 9. Number of Fatal Accidents by CICTT Occurrence Category 

in Non-Scheduled Part 135 (2001-2010). 

28
Figure 10. Number of Accidents by CICTT Occurrence Category in Part 91 (2001-2010). 

Figure 11. Number of Fatal Accidents by CICTT Occurrence Category

in Part 91 (2001-2010). 

29
REPORT DOCUMENTATION PAGE Form Approved

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Contractor Report

 4. TITLE AND SUBTITLE

Frequency of Specific Categories of Aviation Accidents and Incidents 

During 2001-2010 

5a. CONTRACT NUMBER

 NNL12AA09C

 6. AUTHOR(S)

Evans, Joni K.

 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES)

NASA Langley Research Center 

Hampton, Virginia 23681 

 

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National Aeronautics and Space Administration

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NASA

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Langley Technical Monitor: Sharon M. Jones

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14. ABSTRACT

The purpose of this study was to determine the types of accidents or incidents that are most important to the aviation safety 

risk. All accidents and incidents from 2001-2010 were assigned occurrence categories based on the taxonomy developed by 

the Commercial Aviation Safety Team/International Civil Aviation Organization (CAST/ICAO) Common Taxonomy Team 

(CICTT). The most frequently recorded categories were selected within each of five metrics: total accidents, fatal accidents, 

total injuries, fatal injuries and total incidents. This analysis was done separately for events within Part 121, Scheduled Part 

135, Non-Scheduled Part 135 and Part 91. Combining those five sets of categories resulted in groups of between seven and 

eleven occurrence categories, depending on the flight operation. These groups represent 65-85% of all accidents and 68-81% 

of incidents. 

15. SUBJECT TERMS

Aircraft safety; Airline operations; Aviation safety; Civil aviation; Commercial aircraft; Flight operations; Flight safety; 

Injuries; Risk; Taxonomy

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